We have not yet seen what man can make of man.

The major difference between rats and people is that rats learn from experience.

Old age is rather like another country. You will enjoy it more if you have prepared yourself before you go.

A scientist may not be sure of the answer, but he's often sure he can find one. And that's a condition which is clearly not enjoyed by philosophy.

We are only just beginning to understand the power of love because we are just beginning to understand the weakness of force and aggression.

What is love except another name for the use of positive reinforcement? Or vice versa.

No one asks how to motivate a baby. A baby naturally explores everything it can get at, unless restraining forces have already been at work. And this tendency doesn't die out, it's wiped out.